Prediction for the dimensional stability on a paper machine: On-line monitoring system for web shrinkage of paper

Abstract

An on-line method for predicting dimensional stability of paper was developed. The technique is based on monitoring paper web shrinkage in papermaking process by using two sets of equipments for measuring the width of paper web. Each set consists of two laser scanning sensors with intelligent moving mechanism. Relationship between shrinkage of running web and dimensional stability of paper was investigated for several fine papers. It was found that the web shrinkage measured between press and reel correlated well with the expansion in water which indicates dimensional stability of paper. Moreover, the effects of draw between a few sections in a paper machine and of fiber orientation were examined. Draw between wire part and press part affected the web shrinkage but it did not affect dimensional stability of paper. Draw in the dryer section largely affected dimensional stability of paper.